The present invention relates to the field of turbine engines, in particular bypass turbine engines for aircraft. It relates in particular to a discharge valve system for discharging part of an airflow passing through a compressor in a duct of the turbine engine. It also relates to a turbine engine comprising such a discharge system.
A bypass turbine engine comprises, in general terms, from upstream to downstream according to the flow of the gases in the turbine engine, at least one compressor, a combustion chamber and a turbine forming a gas generator that is installed in an inner casing. A movable fan is disposed upstream of the gas generator and in an outer casing that also comprises the inner casing. The air passing through the turbine engine is divided into a primary flow or hot airflow circulating in the gas generator, and a secondary flow or cold airflow coming from the fan and circulating around the inner casing. The hot airflow is compressed by compressor stages of the turbine engine before entering the combustion chamber. The combustion energy is recovered by turbine stages, which participate in driving the compressor stages and the upstream movable fan, and therefore participate in the thrust of the turbine engine. The cold flow also participates in the thrust of the turbine engine.
Turbine engines are also equipped with one or more discharge valve systems known by the English term “handling bleed valve” (abbreviated to HBV), making it possible to remove part of the hot airflow compressed by the compressor, and in particular a high-pressure compressor, and to inject it into the cold airflow with which it mixes. The purpose of this discharge is to stabilise the functioning of the compressor by limiting the phenomena of surge, rotating stall and flutter.
Various types of discharge valve system comprising a flow deflector provided with a plurality of openings oriented in the same direction are known from EP-A2-1 892 399, US-A1-2011/167834 and US-A1-2008/053105. These openings discharge the airflow from the compressor either in the direction of the cold flow or in the direction opposite to the cold flow. Other discharge valve systems comprise a flow deflector having openings with variable diameters depending on their positioning in order to form matrices of particular forms and to vary the rate of the airflow coming from the compressor to be ejected into the cold airflow. These arrangements make it possible to increase the incorporation of the hot airflow discharged into the cold airflow in order to limit thermal stresses on the adjacent structures and/or components that are not designed to withstand high temperatures.
However, these arrangements do not consider or do not offer solutions making it possible to limit disturbances to the cold airflow generated by the fan, which air goes back up the fan operating line in a compression-flowrate field and impacts on the functioning of the turbine engine.
The present applicant has therefore set itself the objective of providing a flow deflector of a compressor discharge valve system that makes it possible to limit disturbance to the cold airflow while limiting thermal stresses on the environment of the duct in which an airflow is circulating.